A helicopter is a type of _____ aircraft.
Rotary Wing
Helicopter turbine engines produce ___________ thrust per pound than piston engines
more
The main forces acting on a helicopter are:
lift, weight, thrust, and drag
Helicopters typically have between ___ and ___ main rotor blades
2-6
Depending on the type of helicopter, main rotor system components can include:
A stabilizer bar, upper/lower swashplates, counterweights, pitch horns, teeter/coning hinges, blade grips, pitch/scissor links, control rods
The function of the flybar is:
To decrease crosswind thrust on the blades and enhance flight stability by keeping the bar stable as the rotor spins
Many helicopters have a horizontal stabilizer located:
On the tail boom
The purpose of the tail rotor is:
To produce an anti-torque force acting perpendicular to the helicopter's longitudinal axis
Wheels on ______ types of helicopters are ________:
some, retractable
A pilot controls a helicopter using:
Pedals, a collective, throttle, cyclic
From a physics perspective, the ______ force is deemed to act through a helicopter's __________:
Total weight, center of gravity
When a pilot banks a helicopter, causing it to turn, _____
The machine's weight increases
In the case of helicopters, lift is produced by _____ moving through the air at a speed sufficient to create
Airfoils, a pressure differential
Thrust acts ________ to the aircraft's ________________________:
parallel to longitudinal axis
Profile drag consists of ___ created by ____ and _____:
None of the above
Vortices produced by spinning rotor blades create:
induced drag
When plotted on a graph, L/DMAX is the point where the helicopter's _____________.
total lift-to-drag ratio is the great especially
A helicopter's potential energy is affected by:
Its height above the ground
Which of the following factors affect the lift produced by spinning rotor blades:
Airfoil coefficient of lift, air density, blade area
What happens when a helicopter's main rotor blades spin rapidly?
The upper and lower sides of each blade experience a difference in pressure
Newton's Third Law of Motion applies to helicopters because:
The spinning main rotor makes the aircraft try to spin in the opposite direction.
When the pilot pushes the cyclic forward:
The main rotor disk tilts forward
Multi-engine helicopters have
A throttle lever for each engine
When the pilot wants the helicopter's nose to move left or right, he or she:
Pushes on the corresponding pedal
For helicopters with a main rotor disk that spins counter-clockwise, the ________ airflow speed happens when each blade reaches the ________ position:
Maximum/ three o'clock (right)
On the advancing rotor blade, lift ________ and the blade __________________:
increases, moves upward
The angle between the ________ of a rotor blade and its direction of motion relative to the ________ is the angle of attack (AOA), which is ________ angle.:
chord line, air, an aerodynamic
The angle of incidence is between the ________ line of each blade and the rotor system's ________:
Chord, plane of rotation
When a helicopter engine ________, a clutch mechanism called a __________________:
fails; freewheeling unit automatically disconnects the engine from the main rotor, allowing it to spin freely.
During an autorotation in forward flight, the rotor disk takes in _______ air and the driven, driving, and stall regions of each blade move ______ along its length (span), but only on the _______ side of the disk:
upward flowing, outboard, retreating.
Where there is too much lift, the main rotor blades will:
flap
Centrifugal force ________ spinning helicopter main rotor blades ________.
Pulls, outward
If left uncorrected, greater lift produced by the advancing side of the rotor disk compared to the lift created by the disk's retreating side could make the helicopter ___________.
uncontrollable
The driven region is ________ the blade tips and normally __ percent of the radius:
nearest, 30
The _______ region is normally between a blade's _______ and _______ regions:
Driving, stall, driven
Because of gyroscopic precession, if a wind gust applies a downward force on the left side of a helicopter's main rotor disk as it spins clockwise (as viewed from above), the movement response occurs at the __ o'clock position:
12
Helicopters experience effective translational lift while transitioning to forward flight at approximately __ to __ knots:
16-24
Maximum ground effect occurs during a hover up to a height equal to _____ percent of the main rotor's diameter
100
A pilot can worsen a helicopter's pendular action by:
Over-controlling the aircraft
The phenomenon of a helicopter sinking into its own downwash is called:
Over settling the aircraft